This year there has been an exciting new study published about altering the prostaglandin (PG) injection in New Zealand dairy cows and that has shown some great results.
Outlined below is the standard program that we have used for treating non-cycling cows in VetSouth over previous years.
The standard program which includes a 2ml injection of prostaglandin (PG) on day 7 has been used successfully for many years. However it was shown in overseas studies that a 2ml dose might not be an adequate dose in the modern dairy cow anymore and higher doses are required. The New Zealand study trialled using a 3ml dose and compared this to our standard 2ml dose. The change is highlighted in red in the graphic below:
When compared to a normal 2ml injection, the 3ml PG injection resulted in the following:
• Increase of 4% in the 4 week in calf rate (statistically significant)
• Increase of 3% in the conception rate (not statistically significant)
By increasing the PG dose slightly at the day 7 injection we are getting a large response in fertility from these programs. This increase in fertility gives a much greater return on investment for only a small increase in cost of the program. As a result, this will become our new gold standard program for treating non cycling cows at VetSouth.
With these latest studies just being released, it is a good time to review with your KeyVet how you will treat non cycling cows this year and come up with the best plan that fits your farm.
Study name: Evaluation of prostaglandin dose for non cycling dairy cows in New Zealand, L Young, 2018
Non Cycling cows return on investment
*Assuming $5.50/kgMS payout, value of extra AB heifer calf is $200, additional 6kgDM feed required to feed a lactating cow vs drycow at a cost of 30c/KgDM.